title: Ectonucleotidase NTPDase3 is abundant in pancreatic β-cells and regulates glucose-induced insulin secretion.
abstract: Extracellular ATP released from pancreatic β-cells acts as a potent insulinotropic agent through activation of P2 purinergic receptors. Ectonucleotidases, a family of membrane-bound nucleotide-metabolizing enzymes, regulate extracellular ATP levels by degrading ATP and related nucleotides. Ectonucleotidase activity affects the relative proportion of ATP and its metabolites, which in turn will impact the level of purinergic receptor stimulation exerted by extracellular ATP. Therefore, we investigated the expression and role of ectonucleotidases in pancreatic β-cells. Of the ectonucleotidases studied, only ENTPD3 (gene encoding the NTPDase3 enzyme) mRNA was detected at fairly abundant levels in human and mouse pancreatic islets as well as in insulin-secreting MIN6 cells. ARL67156, a selective ectonucleotidase inhibitor, blocked degradation of extracellular ATP that was added to MIN6 cells. The compound also decreased degradation of endogenous ATP released from cells. Measurements of insulin secretion in MIN6 cells as well as in mouse and human pancreatic islets demonstrated that ARL67156 potentiated glucose-dependent insulin secretion. Downregulation of NTPDase3 expression in MIN6 cells with the specific siRNA replicated the effects of ARL67156 on extracellular ATP hydrolysis and insulin secretion. Our results demonstrate that NTPDase3 is the major ectonucleotidase in pancreatic β-cells in multiple species and that it modulates insulin secretion by controlling activation of purinergic receptors.
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana.
authors.forename: Samreen K
authors.initials: SK
authors.lastname: Syed
authors.forename: Audra L
authors.initials: AL
authors.lastname: Kauffman
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Beavers
authors.forename: James T
authors.initials: JT
authors.lastname: Alston
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Farb
authors.forename: James
authors.initials: J
authors.lastname: Ficorilli
authors.forename: Marialuisa C
authors.initials: MC
authors.lastname: Marcelo
authors.forename: Martin B
authors.initials: MB
authors.lastname: Brenner
authors.forename: Krister
authors.initials: K
authors.lastname: Bokvist
authors.forename: David G
authors.initials: DG
authors.lastname: Barrett
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Efanov
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011755:Pyrophosphatases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: C092431:6-N,N-diethyl-beta,gamma-dibromomethylene-D-ATP; D004791:Enzyme Inhibitors; D007328:Insulin; D012333:RNA, Messenger; D000255:Adenosine Triphosphate; D011755:Pyrophosphatases; C439652:nucleoside-triphosphate diphosphohydrolase 3; D005947:Glucose
keywords: adenosine 5′-triphosphate; ectonucleotide triphosphate diphosphohydrolase 3; insulin secretion; islets